Just make a regular small PCB and use pins on the edges to mount to the main board. Hybrid will involve designing the circuit, then scaling it ( as the ceramic shrinks during firing) to size, making a set of silkscreen masks for the conductive ink layers, the ceramic isolation layers where they cross over each other, the resistive ink making resistors and then a final screen for identification writing. Then you start with an unfired "green" ceramic sheer, deposit your layers of inks and masks, with a dry cycle between each layer, followed by an inert gas firing to both fuse the substrate into a ceramic, fuse the conductive inks into tracks and fix the resistors. Then you take the finished blank and test it, trim the resistors using either laser or sandblasting, then mount the other components after a solder paste application, reflow then as a final process wire bond the chips or transistors in. Final part is enclose in a hermetic case.
Small board with SMD parts and SM chips is around 1% of the cost, the hybrid only comes into play if you need a high temperature operation unit, or protection from a hostile environment where potting a board will not be enough.